With advances in technology and the continuous development of industrial designs, power supply products have been developed towards the direction of high-level aesthetic perception, high reliability and high performance. In order to satisfy requirements of moulds and processes, housing of a traditional power supply is designed and configured to have an upper cover and a lower cover. With the reference of FIG. 1, which is a schematic view illustrating the structure of the power adapter in the prior art, internal components of the power adapter in the prior art are generally assembled by a way that a PCB (printed circuit board) and the components (not shown) are assembled within the lower cover 20, and then the upper cover 30 and the lower cover 20 being assembled together. It is necessary to allow an assembly tolerance due to the constraints of the assembling process. In such structure, a process gap 10 is generally formed at the junction of the upper cover 30 and the lower cover 20 along the periphery of the housing. The gap not only affects the aesthetics but also tends to introduce dusts, and therefore affecting work efficiency and even resulting in potential safety hazards.
The progress of the moulds and the improvement of the processes give chances to develop industrial designs of the power supplies. The improvement of the process has a significant influence to the improvement of the aesthetic appearances of the power supply products. To meet the aesthetic requirement of gapless, a one-piece design for the housing for the power supply has been applied. With the conventional one-piece design for the housing, however, the input and output terminals of the product usually cannot be effectively fixed, so that the requirements of safety specifications testing cannot be met.